In general, the commercial synthesis and utility of epoxidized natural rubber (ENR) have been well documented. See, for example, http://www.rubber-stichting.ind.tno.nl/natuurrubber/Natuurrubber%2028.pdf, and references therein.
The usefulness of epoxidized elastomers for tire applications are well known, see for example, EP 763564 and WO 00/37555, for their discussion of partial or full replacement of sulfur-containing silane coupling agents by ENR to couple rubber to silica. Further, EP 763564 discloses an epoxidation method using the in-situ formation of performic acid in a two-phase system consisting of cyclohexane/hexane organic phase and an aqueous formic acid/30% hydrogen peroxide phase. This process by which the epoxidized rubber was formed and isolated is rather cumbersome, expensive, and impractical. Therefore, the need still exists for a simple and practical method to prepare epoxidized unsaturated elastomers for tire applications especially if they can be used to wholly or partially displace the need for sulfur-containing silanes to couple rubber to silica.